In order for a pharmaceutical vehicle to be useful as an ophthalmic vehicle, it is necessary that it be non-irritating to the eye, and non-toxic. In order for it to be most effective it must not blur the vision. For certain drugs, unstable in aqueous solution an oil based vehicle is required. For other drugs, which are water soluble and poorly absorbed, it is possible to promote better bioavailability through the use of an oil vechicle (Biopharm. and Drug Disposite, Vol. 7 page 453, 1986). Nevertheless, known oil based ophthalmic vehicles blur the eye. Known vehicles are edible vegetable oils such as cottonseed oil, soybean oil, coconut oil, rapeseed oil, peanut oil, olive oil, palm oil, palm kernel oil, castor oil, sunflower seed oil, wall flower oil, sesame oil; or mineral oils. None of these previously known oils satisfy the 3 above mentioned criteria; all of these oils, while being non-irritating and toxic, blur the vision.
The present invention provides ophthalmic drugs, in an oil based vehicle which is non-irritating, non-toxic and yet does not blur the vision.